I have been experimenting with shorting some bitshares price stable assets into existence. I noticed just now that my position has been liquidated. It looks in this block here like the asset bitGOLD, which tracks the price of an ounce on gold, has had a "black swan" event. You can read this post on the black swan on bit20 to get a better explanation than I could possibly give.
Basically, a black swan occurs when the value of the BTS collateral backing the smart coin drop below 100%. GOLD had been in margin call for a few days now, which gave buyers a chance to sell bitGOLD at a 10% premium against the margin. Normally, this would entice speculators to short more GOLD into existence to sell into the margin call. It seems though, that in these uncertain time, noone was willing to take that risk.
Where do things go from here? bitGOLD can still be traded and settled, but no more can be created. There is currently a BSIP (bitshares improvement proposal) to reset assets affected by black swan events, so they can trade normally again. So this can theoretically be fixed on the blockchain level. But the question remains, what damage to the reputation and "brand" of bitshares assets will this do?